Association between particulate matter exposure and influenza in Wuhan, Hubei, 2022–2024

Objective To investigate the short-term association between ambient particulate matter exposure and reported influenza incidence in residents in Wuhan, Hubei province.

Methods The incidence data of influenza reported in Wuhan from 2022 to 2024 were collected through the Infectious Disease Surveillance System of the China Disease Prevention and Control Information System, and local air pollution and meteorological data during the same period were collected too. A generalized additive model was used to evaluate the associations of fine particulate matter (PM_2.5) and inhalable particulate matter (PM₁₀) concentrations with daily reported influenza cases. Single-day lags (lag0–lag7) and moving average lags (lag0–1–lag0–7) were used to analyze the lagged effects of short-term particulate matter exposure. Stratified analyses were performed by age, sex, season, and area of residence, and two-pollutant models were constructed for sensitivity analyses.

Results A total of 459,469 influenza cases were reported in Wuhan from 2022 to 2024, with a daily average of 419.22 cases. The daily average concentrations of PM_2.5 and PM₁₀ were 37.21 and 57.69 μg/m³. In single-day lag analysis, PM_2.5 and PM₁₀ had the greatest effect at lag 0 days. When the concentration of PM_2.5 and PM₁₀ increased by 10.00 μg/m³, the reported influenza cases increased by 3.88% and 6.57%. In the moving average lag analysis, the harmful effects of particulate matter increased with the increase of cumulative exposure days, and the influenza cases increased by 5.67% and 11.52% for each 10.00 μg/m³ increase of average exposure concentrations of PM_2.5 and PM₁₀ at 0-7 days (lag 0-7), respectively. In stratified analysis, the effect estimates after particulate matter exposure were higher in people aged over 60 years than those in other age groups, and higher in women than in men.

Conclusion Short-term exposures to PM_2.5 and PM₁₀ were positively associated with daily reported influenza cases in Wuhan during 2022–2024, and these associations are modified by age and sex.